Nest also does this, seems very strange to bet on such an experimental feature. It's very convenient to use though.

Yes, Nest uses decorators and the reflect-metadata package to get information about them dynamically. Annotations/decorators in other languages are fine, but in JavaScript/Typescript I feel the risk of using them as a dead end feature. I'd like the proposal as much progress as possible, but it's been quiet. In the meantime, a Typescript Nest like system without annotations could be better.